High-reactance transformer



Jan. 15, 1929. A. B. HENDRICKS. JR

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Patented Jan. 15, 1929.

UNITED STATES.

PATENT OFFICE.

ALLAN B. HENDRICKS, JR., OF PITTSFIELD, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION NEW YORK.

HIGH-REACTANCE TRANSFORMER.

Application filed April 28, 1928. Serial No. 273,723.

v My invention relates to high reactance transformers. High reactance in a transformer is often desirable or necessary in order toliinit to a safe value the current supplied by the secondary winding of the transformer. The reactance of a transformer mcreases with the leakage magnetic flux.

Transformers with high leakage flux and reactance have been used in which the magnetic core has three legs connected by end yokes, the two windings being spaced apart on the central or winding leg which has side extensionseprojecting between the two windings to provide shunt magnetic paths for leakage flux. The effectiveness of the side extensions in increasing the leakage flux and reactance is determined by the thickness of the air gaps between their outer ends and the outer two. core legs. High reactance transformers of this type'are useful for operating bells, electric toys and other apparatus requiring small amounts of power. lhe general object of the invention is to prov de a high reactance transformer of .the general construction just referred to but arranged so that the core parts may be assembled in different relative positions to provide different desired reactances.

The invention will be better understood from the following description taken in connection with the accompanying drawing in which Fig. 1 is a perspective view of a trans former constructed in accordance with the invention, and Figs. 2 and 3 are diagrammatic face views of the transformer shown in Fig. 1 but with the core parts assembled in different relative positions.

Like reference characters indicate similar parts in the different figures of the drawing. The particular transformer shown in the drawingv includes a' magnetic core having a hollow ring or shell 10 and a winding 11 with integral oppositely disposed side extensions 12. Primary and secondary windings 13 and 14 surround the windin leg 11 and" are spacedapart with the side extensions 12 projecting between them in 0pposite directions from the winding leg. All 'the core parts should, of course, be built up of sheets or laminations as indicated in Fig. 1 to prevent excessive eddy-currents. The winding leg '11 is just long enough to fit tightly across the opening in the shell 10 so that after the 13 and'14 have been placed on the winding leg it may be forced into the shell and held in place by friction.

The inner surface or face of the shell 10 and the ends of the winding leg 11 are so formed that the shell and winding leg may be assembled in different relative angular positions. referring particularly to Fig. 2, the inner face of the shell has four sections 15, 16, I 17 and 18. The oppositely disposed sections 15 and 17 are everywhere equidistant from and .concentric about a common center, so that the winding leg 11 may be assembled and held between them in different angular positions relatively to the shell 10. The sec: tions 16 and 18, however, are eccentric about the common center of sections 15 and 17 so that their distances vary from this center.

The angular positions of the side extensions 12.relatively to the shell 10 are determined by the corresponding position of the As shown in the drawing and.

winding leg itself in'the shell. It will now be apparent that the thickness of the spaces or 'gaps'19 between the inner face of the shell 10 and the outer ends of the extensions 12 will be different for different angular positions of the winding leg 11 relatively to the shell. Fig. 2 shows an assembly in which the outer ends of the extensions 12 are very close to or touch the inner face of the shell 10 so that the reactance of the transformer is extremely high. Figs.'1 and 3 show another assembly in which there is a considerable space or gap 19 between the outer end of each extension 12 and the innerface of the shell 10 so that the reactanceof the transformer is very much less thanwith the assembly shownin Fig. 2. It is obvious that any desired reactance between these two extremes may be roduced by assembling the shell 10 and win ing leg 11 in such relative angular positions as to result in the proper thickness of the gaps 19. Thisis of g considerable advantage because all the parts may be exactly alike and any desired reactance within reasonable limits may be secured merely by assemblin the parts properly.

The invention hasi trating and describing a specific form thereof but it will be apparent that various changes may be made without departing from the scope of the invention as defined.

. in the appended claimseen explained by illus- What I claim as new and desire to. secure by Letters Patent of the United States is sections formed to receive said winding leg in a plurality of different angular positions relatively to said shell, and .the inner face of said shell having a section formed to provide different spacings between it and the outer end of said extension for said diiferent angular positions of the winding leg.

2. A transformer including a magnetic core having an outer hollow shell and a winding leg extending across the opening in said shell, said winding leg having an integral side extension, the inner face of said shell having two oppositely disposed sections concentric about a common center to receive said winding leg in a plurality of different angular positions relatively to said shell, and the inner face of said shell having a section eccentric to said common center to provide different spacings between it and the outer end of said extension for said ilifl'er'ent angular positions of the winding 3. A transformer including a magnetic core having an outer hollow shell and a winding leg extending across-the-opening in said shell, .said winding leg having integral op ositely disposed side extensions, t-herinner face of said shell having two oppositely disposed sections formed to receive said winding leg in a plurality of difi'erent angular positions relatively to said shell, and the inner face of said shell having two other oppositely disposed sections formed to provide different spacings between them and the outer ends of said extensions for said difl'erent angular positions of the winding leg.

4. A transformer including a magnetic core having an outer hollow shell and a winding leg extending across the opening in said shell, said winding leg having integral oppositely disposed sections concentric about a -connnon center to receive said winding leg in a plurality of different angular positions relatively to said shell, and the inner face of said shell having two other oppositely disposed sections eccentric to said common center to provide different spacings between them and the outer ends ofsaid extensions vfor said diiferentangular positions of the 

